In recent years, along with the aging of society and the westernization of food culture, the number of patients with lifestyle diseases is increasing. Arteriosclerosis is also one of lifestyle diseases, and if the symptoms progress, a disease that affects human life, such as an aortic aneurysm, may be developed. If the symptom of the aortic aneurysm progresses, in order to prevent its rupture, the aorta including the lesion site is replaced with an artificial blood vessel by blood vessel prosthesis implantation surgery.
The artificial blood vessel, of course, should not leak plasma as well as blood cells and is also required to have compatibility with human bodies, durability, and safety and must be able to be easily anastomosed with a blood vessel by surgery.
Accordingly, a variety of artificial blood vessels save been developed conventionally. For example, a fabric artificial blood vessel made by knitting or plain weaving a polyester fiber or a polytetrafluoroethylene (PTFE) artificial blood vessel having numerous fissures made by rapidly stretching tubular-shaped PTFE is generally used (see NPL 1).
An artificial blood vessel including an inner layer constituted of a nonwoven fabric layer of an ultrafine fiber having a diameter of 10 μm or less formed by an electrospinning method and a cover material disposed on the outside of the inner layer, wherein the nonwoven fabric layer and the cover material are firmly adhered to each other, has been developed (see PTL 1).
However, these artificial blood vessels are not absorbed by living bodies even after transplantation. Accordingly, if an artificial blood vessel is infected due to, for example, dental treatment, the treatment is very difficult, and surgery for replacement of the artificial blood vessel may be necessary. In addition, since nutrient blood vessels cannot enter the artificial blood vessel, the intimal cells migrating to the lumen of the artificial blood vessel may necrotize.
Accordingly, in recent years, artificial blood vessels made from bioabsorbable fibers that are absorbed in the bodies after transplantation have also been developed. However, existing bioabsorbable artificial blood vessels are constituted of bioabsorbable fibers having rapid biodegradation and absorption rates, such as a copolymer of lactic acid and caprolactone, so as to be decomposed and absorbed promptly after transplantation (see PTL 2).
Accordingly, the strength of the artificial blood vessels is also rapidly decreased, and the artificial blood vessels cannot be used in a cardiovascular system that is always exposed to high pressure from the lumen, such as an artery. Even if such an artificial blood vessel is used in an artery or the like, since the artery or the like is replaced with a diseased tissue, such as a scar tissue, calcification, or an aneurysm, complete regeneration or treatment is not achieved.